theultimatehero

I want to follow up on THIS thread because while struggling my ass off to figure this out, I came across a shit load of threads that never had a legitimate follow up to help people like myself. I hope this has some helpful information for you all!

To recap:

I had purchased a used Cusco MZ diff internal (aka carrier). I had been told when I bought the internals that it had been disassembled and rebuilt by a "Certified Cusco Dealer" in the recent past. I went ahead and installed the diff and had a really terrible time trying to figure out which axles (Side shafts or axle stubs) I needed. None of the available axle options seemed to work and I was very frustrated. I eventually got a tip (ironically from a guy at KAAZ I had called to see if they had any advice). He mentioned that it was possible somehow the diff had been taken apart and assembled BACKWARDS! Let me try to explain

I eventually brought the diff to Kenji at Cusco USA HQ in Huntington Beach. This man is a class act. I did not buy the diff from Cusco (again it was used). I brought it to him at the end of his day and he stayed nearly 3 hours late getting it sorted out for me. Including drilling one of the screws out of the housing, because whoever put the thing together was a real fucktard. The housing bolts dont need loctite, the ring gear holds everything together when installed.

Shameless plug: Cusco (Kenji specifically) really hooked me up taking this thing apart. Putting it back together correctly, after inspecting all of the clutch plates. Then even torque testing to see it works correctly. Did I mention all this at NO charge? I WILL be buying more Cusco products as Kenji alone has bought my business.

And back to real info. At first we really didn't know which diff I had. By following this chart we came to the conclusion I have an LSD 263. This alone was one of the keys to figuring things out.



Along with that chart we used these two pages of side shaft information to determine which shafts would indeed fit correctly into these internals. In my case "F" type side shafts. These are the standard shafts in both USDM and JDM VLSD pumpkins. Only the USDM version came with 6-bolt flanges while JDM seem to have 5 bolt flanges (which I have).





Now finally we are getting somewhere. The only problem is this: If we are fairly certain I have the right axles for my diff then WHY DON'T THEY FIT?

Inside these LSDs (same idea for all clutch LSDs, including KAAZ, Carbonetic etc.) there are two side gears. These gears are splined to match the axle shafts and they are what turn with your axles and connect your axles to the clutches and gears. They also have grooves cut in the splines that match with the axles. Sometimes these grooves will have a c-ring installed inside, sometimes they don't. It will depend on your side shaft set up. In my case (the F type shaft) on the driver side has a ring installed in the SHAFT therefore the side gear in the diff has a small groove for the ring to click into. The passenger side shaft has a small groove while the SIDE GEAR has the c-ring installed. The problem is the side gears were installed opposite(inverted) of what they are supposed to be! The geometry and spacing when installed in the housing means NONE OF THE STANDARD SHAFTS FIT CORRECTLY.

Now for picture time. First we had to drill that stuck bolt out of the housing, the bolt head completely stripped. Again, they DO NOT need to be torqued heavily or loctited, don't do it.



Next Kenji disassembled the entire thing and inspected all of the clutch plates.







They look good!

Of course these are the side gears in question. It is clear they are different and must be installed in the correct side. Keep in mind though, they CAN be installed incorrectly and the diff will both go together and function.





At this point all we had to do was re-build the entire thing with the side gears installed correctly. For reference here is the Cusco manual pages that indicate which gear goes on which side. This manual is only available through Cusco and it is only in Japanese.



The highlighted box with the "C" in it indicates the C clip, corresponding to side gear "2" in the previous picture. Thus the one with the C clip should be on the passenger side. As I mentioned before this was not the case.



Finally. The whole thing went back together with no trouble. Kenji set the engagement to 60% for me, as this is a track and street car so I don't need really violent lock up. He even tested the torque spec to see it engaging at 60%.



I hope this helps someone some day. The real lesson is when re-assembling a diff make damn sure you have everything installed correctly. Get the manual and triple check that the components are going in the intended place, seeing as these gears can easily be confused. Time to hit the canyons!

jr_ss

Great write up! Thanks for taking the time to do this, I'm sure it'll help many.

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My SR20VET